How does increasing antenna gain affect the transmitter power required for the same link margin?

• A. It has no effect on transmitter power.
• B. It reduces transmitter power required.
• C. It changes only the receiver sensitivity.
• D. It increases required transmitter power.

Answer: (B)

Increasing antenna gain on the transmitter improves the link budget by boosting the effective power that reaches the far end. Higher transmit gain concentrates more of the power in the direction of the receiver, effectively increasing the transmitted signal strength (EIRP). For the same path loss and the same receiver sensitivity, you can reduce the actual transmitter power while still delivering the required received power. In other words, doubling the transmit antenna gain lets you cut the transmitter power roughly by the same factor to maintain the same margin. The receiver’s sensitivity remains unchanged, and the margin is preserved because the increased gain compensates for the loss along the path.